I potty trained my chinchilla with fleece first (even though her whole cage is just about fleece anyway), by putting a fleece pillow where ever she pee'd the most. For her, she would always pee on her ledges (ugh!) so I had no trouble finding her bathroom spots. If you have any spare fleece pillows laying around, you could try it that way.
After she got used to using her "wee pad", I moved it to the spot where I wanted (ie top corner of the cage). She was very good about changing potty spots.
And again, after she got used to her new spot, I simply changed it to shavings and haven't had a problem with it since. She took very well to the shavings, which surprised me because her first potty training attempt ended with shavings all around the cage for weeks.
If your chin doesn't take to peeing in a glass baking pan right away, try leaving out the pan itself and just use the pillow. You'd preferably want to avoid doing that on the shelves for obvious reasons.
Or, of course, you can take the straight and easy path and just fill a glass pan with shavings and put it in your chins potty spot and see how that goes!